IB Biology Topic C1.2.12 Oxidation and Decarboxylation of Acetyl Groups in the Krebs Cycle Revision Notes (HL)

IB Biology Topic C1.2.12 Oxidation and Decarboxylation of Acetyl Groups in the Krebs Cycle Revision Notes (HL) | RevisionDojo

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The Krebs Cycle Fully Oxidises the Acetyl Group

In the link reaction (covered in C1.2.11), pyruvate is oxidised and decarboxylated to form acetyl-CoA.
Acetyl-CoA carries a 2-carbon acetyl group that still holds chemical energy.
The Krebs cycle breaks this acetyl group down fully to release that energy.

Definition

The Krebs cycle

The Krebs cycle (also known as the citric acid cycle) occurs in the mitochondrial matrix and is a key part of aerobic respiration.

How the Krebs Cycle Works Step by Step

Step 1: The acetyl group enters the cycle
1. The acetyl group (2C) joins a 4-carbon molecule called oxaloacetate to form the 6-carbon molecule citrate.
2. Coenzyme A is released and recycled back to the link reaction.

Exam technique

You mainly need to remember two named molecules: citrate (6C) and oxaloacetate (4C).
Acetyl (2C) plus oxaloacetate (4C) gives citrate (6C).

Step 2: Oxidation removes hydrogen

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The Krebs Cycle Fully Oxidises the Acetyl Group

In the link reaction (covered in C1.2.11), pyruvate is oxidised and decarboxylated to form acetyl-CoA.
Acetyl-CoA carries a 2-carbon acetyl group that still holds chemical energy.
The Krebs cycle breaks this acetyl group down fully to release that energy.

Definition

The Krebs cycle

The Krebs cycle (also known as the citric acid cycle) occurs in the mitochondrial matrix and is a key part of aerobic respiration.

How the Krebs Cycle Works Step by Step

Step 1: The acetyl group enters the cycle
1. The acetyl group (2C) joins a 4-carbon molecule called oxaloacetate to form the 6-carbon molecule citrate.
2. Coenzyme A is released and recycled back to the link reaction.

Exam technique

You mainly need to remember two named molecules: citrate (6C) and oxaloacetate (4C).
Acetyl (2C) plus oxaloacetate (4C) gives citrate (6C).

Step 2: Oxidation removes hydrogen

Definition

Paywall

(on a website) an arrangement whereby access is restricted to users who have paid to subscribe to the site.

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Note

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam quis nostrud exercitation.

Excepteur sint occaecat cupidatat non proident

Tip

Lorem ipsum dolor sit amet, consectetur adipiscing elit.
Sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris.
Duis aute irure dolor in reprehenderit in voluptate velit esse cillum.

A - Unity and Diversity9 subtopics

B - Form and Function10 subtopics

C - Interaction and Interdependence9 subtopics

D - Continuity and Change12 subtopics

IB Biology Topic C1.2.12: Oxidation and Decarboxylation of Acetyl Groups in the Krebs Cycle Notes

A - Unity and Diversity9 subtopics

B - Form and Function10 subtopics

C - Interaction and Interdependence9 subtopics

D - Continuity and Change12 subtopics

The Krebs Cycle Fully Oxidises the Acetyl Group

How the Krebs Cycle Works Step by Step

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The Krebs Cycle Fully Oxidises the Acetyl Group

How the Krebs Cycle Works Step by Step

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

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